EXHIBIT 23.1 - CONSENT OF INDEPENDENT AUDITORS

     We consent to the incorporation by reference in the Registration  Statement
(Form S-8 No.  333-56123)  pertaining to the  Bioanalytical  Systems,  Inc. 1997
Employee Incentive Stock Option Plan and in the Registration Statement (Form S-8
No.  333-56127)  pertaining  to the 1997  Bioanalytical  Systems,  Inc.  Outside
Director Stock Option Plan of our report dated November 1, 2001, with respect to
the   consolidated   financial   statements  of  Bioanalytical   Systems,   Inc.
incorporated  by  reference  in its 2001 Annual  Report (Form 10-K) for the year
ended September 30, 2001 filed with the Securities and Exchange Commission.


                                        /s/ Ernst & Young LLP


Indianapolis, Indiana
December 27, 2001